the widespread usage of pesticides leads to the need of improving the knowledge on their environmental behaviour in order to decrease the risks to biota, as well as the water, soil, and food contamination. the influence of the earthworms eisenia foetida on the dissipation of glyphosate, the herbicide bioaccumulation in the worms and the influence of the herbicide on the endogeneous microbial bioactivity were evaluated in an agricultural soil sample treated with aqueous solution of 14c-glyphosate. the studies were performed in systems maintained for 2 or 4 months containing soil samples treated with three different concentrations of 14c-glyphosate and containing or not the earthworms. after these periods, soil samples and the earthworms were extracted and combusted for radiocarbon quantification by liquid scintillation counting (ecl). the microbial bioactivity was evaluated through the activity of the dehydrogenase enzyme. results showed that earthworms did not influence the soil dissipation of glyphosate, independently of the contact period, although they bioaccumulated glyphosate residues, proportionally to the contact period. the higher period favoured the 14c-non-extractable or bound residues production. soil bioactivity was not altered, neither by the earthworms, nor by the treatments or time after treatments.